The MPLS WG Archive

[Nhat Thanh Hoang <Nhat.T.Hoang@telia.se>]

Hi, Alexander

As I know RSVP for traffic engineering that uses in MPLS context is
unidirectinal, which means you need to configure at least two
constraint-based LSPs (ingress--->egress and ingress<---egress), if you want
a bidirectional path.

/Nhat Thanh
Telia Research AB

-----Original Message-----
From: Alexander Marhold [mailto:Alexander.Marhold@proin.com]
Sent: den 30 november 2000 07:00
To: eduard metz; rschell@megapathdsl.net
Cc: mpls@UU.NET
Subject: RE: MPLS for UDLR


As I have seen no other answers my assumption on that

LSP is unidirectional, but RSVP is not,
RSVP tries to send the PATH message using the ERO ( Path information ) in
the reverse direction. This fails on an UDLR.
For me it seems that RSVP would need additional information (maybe even an
extension)to successfully take care of that problem.

IMHO this is a general RSVP problem and thus maybe an issue for the
corresponding IETF WG's dealing with RSVP.

But maybe someone more knowledgeable can shed some light on that

regards
Alexander

> -----Original Message-----
> From: owner-mpls@UU.NET [mailto:owner-mpls@UU.NET]On Behalf Of eduard
> metz
> Sent: Wednesday, November 29, 2000 12:16 PM
> To: rschell@megapathdsl.net
> Cc: mpls@UU.NET
> Subject: RE: MPLS for UDLR
>
>
>
> Hi Robert,
>
> interesting issue, since MPLS LSP are basically uni-directional I
> think this
> should work (although I'm not really in to UDLR ...).
>
> You may want to redirect your question to cisco-nsp@puck.nether.net, as it
> concerns some implementation specific issues. You probably will get better
> feedback on that list ...
>
> cheers, Eduard
>
> -----------------------
>
> I am looking for ways to implement certain traffic engineering and QoS
> features over satellite links using MPLS.
>
> Does any router support Unidirectional Link Routing (UDLR) using
> MPLS as the
> tunneling encapsulation? I have tried this with Cisco 7200 and 7500 series
> boxes (with latest T-train IOS) without success. It seems that
> UDLR is able
> to use only GRE tunnels. In my view, MPLS would be ideally suited to this
> purpose because it is lightweight (only 4 bytes) and satellite bandwidth
> tends to be scarce.
>
> In general, I have had trouble getting MPLS TE tunnels to work when the
> physical interfaces for send and receive are different. This may
> be more of
> a problem with OSPF than with the tunnel mechansim itself. Any thoughts?
>
>
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